Pinion gear transmission

ABSTRACT

Pinion gear transmission comprising a pinion shaft, a pinion wheel at one end of said shaft, connecting means at the opposite end of said shaft for connecting said pinion wheel and shaft to drive means, a housing, bearing means for rotatably supporting said pinion shaft and connecting means relative to said housing, said pinion shaft and connecting means movable axially relative to one another to preload said bearing means and means for permanently fixing said shaft and connecting means with said bearing means preloaded, said shaft, bearing means and connecting means forming an integral unit.

United States Patent [191 Asberg [451 Feb. 19, 1974 1 PlNlON GEARTRANSMlSSlUN [75] Inventor: Sture itsberg, Savedalen, Sweden [73]Assignee: SKF Industrial Trading and Development Co. N.V., Overtoom141-145 Amsterdam, Netherlands [22] Filed: June 28, 119711 [21] Appl.No.: 157,594

[52] US. Cl. 741/4241 [51] lint. Cl. F1611 11/1141 [58] Field of Search74/423, 424, 710, 713; 308/187, 191, 193, 195

[56] References Cited UNITED STATES PATENTS 1,956,237 4/1934 Hughes74/424 3,375,727 4/1968 Nasvytis et a1 74/423 X 783,168 2/1905 Baker74/713 899,891 9/1908 Niclausse 74/713 3,385,133 5/1968 Terao 74/7103,290,101 12/1966 Recknage] 308/187 r, y aura/,

1,335,525 12/1931 Robbins 74/710 X 1,369,210 2/1921 Zimmerman. 74/424 X1,708,710 4/1929 Vincent 74/424 Primary Examiner-Benjamin W. WycheAssistant Examiner-Frank H. McKenzie, Jr. Attorney, Agent, orFirm-Howson & Howson; Eugene 1E. Renz, Jr.

[57] ABSTRACT Pinion gear transmission comprising a pinion shaft, apinion wheel at one end of said shaft, connecting means at the oppositeend of said shaft for connecting said pinion wheel and shaft to drivemeans, a housing, bearing means for rotatably supporting said pinionshaft and connecting means relative to said housing, said pinion shaftand connecting means movable axially relative to one another to preloadsaid bearing means and means for permanently fixing said shaft andconnecting means with said bearing means preloaded, said shaft, bearingmeans and connecting means forming an integral unit.

117 Ciairns, 5 Drawing Figures PllNllON GEAR TRANSMISSION The presentinvention relates to a pinion gear transmission comprising a pinionwheel, a pinion shaft and connecting means at the end of said shaftopposite the pinion for connecting it to a drive means, a housing partand roller bearing supporting the pinion shaft within the housing part.Pinion gear transmissions of this kind are well known. They are used ina great number of automobile cars in particular to transmit the drivecouple from a longitudinally extending shaft towards transverselyextending wheel driving shafts, the pinion gear engaging a crown wheelwithin a transmission housing. Transmissions of said kind have towithstand loads of largely varying magnitude. This requires preloadingof the bearings of the pinion shaft and a precise adjustment of piniongear wheel and crown wheel with respect to each other. Preloading andadjustment are performed by means of chimbs or rings between theshoulders of the bearing ring and shoulders on the housing and/or shaft.This operation is difficult, requires high skill and time and isextremely difficult to perform in case of repair.

Further problems in the design and construction of this kind oftransmission have to do with:

a. the rigidity of the constructional parts such as radial bending andaxial elastic deformation,

b. surface contact deformation of all the parts,

0. heat elongation in operation, and

d. machining tolerances between the several parts forming theconstruction, such as pinion shaft, housing, seats and shoulders for thebearings and the bearings themselves.

Purpose of the invention is to provide a pinion gear transmission whichtakes away part or all of the abovedescribed disadvantages and accordingto the invention, this has been achieved primarily in that the shaft,the pinion, the connecting means and the inner races of the bearingsform a unit which after its assembly cannot be taken apart. Thisassembly has, of course, the proper preloading of the pinion shaftbearings. The unit can be made in such a way that the proper adjustmentof the pinion gear wheel with respect to the crown wheel is included aswell. It, however, is also possible to allow separate adjustment of thegear wheels with respect to each other which can be achieved byproviding a separate housing for the pinion gear, which housing isflanged to the transmission housing in a known way.

ln the sense of a provision of the unit, the said connecting means canextend radially outwardly beyond the inner races of the bearing. Thismeasure known per se now makes more sense than in combination withsplines and a locking nut as known.

It is, according to the invention, also possible to provide the unitwith complete bearing means, which means not only the inner racesurfaces, but also the rolling elements, cage and outer rings, whichsimplifies mounting of the unit. A further simplification is obtained inthat the housing part is a common race ring for the bearings, having aradial flange for connecting it to the transmission housing.

According to the invention, the shaft, the pinion and the connectingmeans now can consist of only one work piece. This work piece can be ahollow pressed or forged metal body closed at one end having pinion gearteeth and race surfaces. Such a work piece is easy to manufacture andhas the advantage that the machining of the teeth and of the racesurfaces can be performed in one fixture. A further advantage of thehollow structure is that proper cooling takes place there where the heatis generated between the teeth.

By those measures, a construction is obtained which can be very rigid,does not materially change its dimensions at elevated temperatures dueto the cooling and its possible short axial length, has less tolerancesand the accuracy of the bearing surfaces with respect to the gear teethis better. If axial-radial bearings are used, the contact lines coverbetter the axial distance between the load at the connecting means andthe load line at the gear wheel. With respect to bending loads occurringin the construction, this provides a much better position than with theknown constructions.

According to the invention, it is, however, also possible that the shaftand pinion form one work piece and the connecting means are undetachablysecured to the shaft. This can be done, e.g. by welding during thepreloading operation of the bearing elements during assembly. lt is alsopossible that the shaft and connecting means form one work piece and thepinion is unde' tachably secured to the shaft. The assembly andpreloading can be performed in the same way as described above.

By those constructions, it is also possible to enlarge rigidity, reducethe axial dimensions and reduce the tolerances. It, however, remainspossible to make use of conventional rolling bearings having separateinner and outer race rings.

When only one work piece is used, e.g. the hollow pressed or forged workpiece, preloading takes place by the insertion of the balls. With thisembodiment, it is possible to provide the race surfaces for the rollingbearings on both sides of the pinion teeth.

By this measure, rigidity can further be improved while in particularwith one row ball bearings on either side of the teeth, the axiallength. remains short with only a very short portion protruding from thehousing at the side of the connecting means.

The construction can be made also in such a way that the pinion andconnecting means have concentric shaft forming cylindrical portionsfitting into each other; the connection then also can be performedduring the preloading operation by means of welding. In that case, theinner race surfaces can be provided in the outer surface of one and/orboth shaft forming concentric portions.

Although separate race rings in some embodiments of the unit accordingto the invention are possible, it is advantageous to machine the racesurfaces in the part or parts of the work piece itself reducing in thisrespect the number of tolerances considerably.

The entire construction can be such that the pitch diameter of thebearing located between the pinion and the connecting means is largerthan the outermost diameter of the pinion teeth. This enlarges thebearing capacity and in some cases, simplifies the assembly.

A construction of very short axial length now is possible, having thebearings as close as possible to the gear teeth. It is of furtheradvantage to dimension the parts such that the inner diameter of thecage is larger than the said outer most diameter of the teeth to alsosimplify the assembly of the bearing.

In all embodiments according to the invention, the axial length of thepinion gear transmission can be con siderably reduced as compared toknown embodiments the degree of length reduction depending upon thedesign such as the presence of separate race rings or not.

With all embodiments according to the invention, the preloading isperformed during manufacturing and the adjustment can be included ornot. In case of repair, the cheap unit has to be replaced which nolonger requires skilled labor. The number of places where surfacecontact deformation can take place is reduced as well as the number ofplaces where tolerances occuring during machining play a role. A largerdiameter is possible and the shorter length reduces radial bending underthe load occurring between the gear wheels and contributes to therigidity. The short length reduces heat elongation.

The construction of the unit accordingly allows the possibility to useall kinds of cheaper manufacturing methods.

In all cases, the cardan coupling may form an integrated part of theconnecting means, due to the fact that no nut is present at the end ofthe pinion shaft.

Large ball and pitch diameters are possible, and with the embodiments ofshort length, the working angle can be chosen such that the working lineof the forces goes through the area where the working angle intersectsthe axis of the shaft so that there is no or only a very short overhangreducing bending forces.

The gear function no longer is spoiled by the weakness of theconstructional parts resulting from tolerances and elastic deformationso that higher precision can be easily achieved.

The invention now will be further elucidated with reference to thedrawings.

In the FIGS. 1 to 5 inclusive different embodiments of the invention areshown in cross section.

The embodiment of FIG. 1 of all embodiments shown in the Figs. has thesmallest difference with respect to the known constructions. In FIG. 1,the transmission housing has been indicated in general by thereference 1. In said housing by means of bearings 2 a crown wheel 3,secured to a differential gear transmission 4, has been supported.

The pinion gear is supported by means of bearings in the housing part 5.

According to the known constructions, shaft and housing part areprovided with shoulders and the bearings have outer and inner race ringswhile the connecting means are secured to a splined portion of the shaftend and held in place by means of a nut on the screw threaded outer endof the shaft, which nut plays an important role in the preloading of thebearings.

In the construction shown in FIG. 1, the pinion gear wheel 6 has a shaft7 and the connecting means are formed by a sleeve 8 having a flange 9.

The housing 5 has a cylindrical bore 10 accommodating the outer raceringsll and 12 of the two axially spaced bearings, which race rings 11and 12 are spaced apart by a cylindrical sleeve 13, the ring 11 engaginga shoulder 14 of the housing. The inner race ring 15 fits upon the shaft7 and engages a shoulder 16 of the pinion wheel. The other inner racering 17 fits upon the shaft 7 and rests against the sleeve 8 of theconnecting means 9.

After assembling the above-mentioned parts with finally putting thecylindrical sleeve portion of the sleeve 8 over the cylindrical end ofthe shaft 7, the bearing is preloaded by pressing the connecting meansand the pinion in opposite directions towards each other. When thedesired degree of preloading is achieved, the sleeve 8 and the shaft 7are permanently connected by means of welding, which can be done in anumber of well known ways, such as electrobeam welding, spinwelding,etc.

The unit obtained in this way is locked in the housing by means of twohalf rings 18.

The axial length of this embodiment as compared with the knownembodiment is reduced by the fact that the splined shaft end and thescrew threaded end no longer exist. The construction of the shaft itselfis simple since it has only a cylindrical outer surface.

The construction shown in FIG. I shows balls for the bearings, but itwill be clear that also other rolling elements can be used.

FIG. 2 shows an embodiment which axially has a considerably shorterlength. In this embodiment, pinion and shaft 19 and 20 respectively forman integral body and the connecting means again have the form of asleeve 21 with flange 22, which parts are permanently connected, e.g. bymeans of welding.

In this embodiment, the race surfaces 23 and 24 of the two ball bearingsare machined in the material of pinion shaft 20 and sleeve 21 itself.The outer part of the assembly is formed by a sleeve 25 with a flange 26to enable the unit obtained in this way to be secured to the housing 27.Adjustment of the gear wheels with respect to each other can beperformed by means of chimbs between flange 26 and housing 27. Also, inthis sleeve the race surfaces 28 and 29 are directly machined in thematerial of the sleeve 25 itself. 30 indicates a sealing of the bearing.In this embodiment, sleeve 21 and shaft axially abut each other and areaxially machined so accurately that the correct preload value has beenobtained when the parts are welded to gether.

This embodiment is considerably shorter in axial direction.

The only surfaces between which tolerances play a role are the racesurfaces with respect to the balls.

FIG. 3 shows an embodiment in which the pinion, the shaft and theconnecting means form one integral part 42 made by pressing or forgingsteel into a hollow body, the hollow space extending through almost theentire length of the integral body. The race surfaces 41 for the ballsare machined in the body 42 itself, and the same holds true for theouter flanged sleeve 43, which serves for connecting the unit to thehousing 44.

The axial length of this embodiment is very short and its diameter verylarge. From the load line of the gear wheels as indicated with 45 andthe working line of one of the roller bearings indicated with 46, itfollows from FIG. 3 that the two load lines 45 and 46 intersect the axis47 in one point which means that there will be minimum bending stressesin the body 42 and a high capacity large diameter ball bearing ispossible.

FIG. 4 shows another development of the constructive principle of FIG. 3by using a hollow forged integral body in which the gear teeth of thepinion wheel are machined in the body between the race surfaces 48 and49 of the two ball bearings. The outer sleeve 50 with flange 51, ofcourse, now has a greater axial length and is provided with an opening52 through which the crown wheel can engage the teeth 53 of the pinionwheel.

The preloading of the embodiments shown in FIGS. 3 and 4 has to takeplace by the insertion of the balls.

As shown in F103, the pitch diameter of the largest bearing is greaterthan the outermost diameter of the gear teeth of the pinion wheel. ltwill be clear that this pitch diameter even can be still larger as shownin FlG. 3. The inner diameter of the cage of the bearing is such that itcan be easily shifted over the gear teeth.

FIG. shown an embodiment based on the same principle as the oneaccording to FIGS. 3 and 4 with this difference, however, that thepressed or forged body 5d has integral connecting means in the form ofeyes 55 to accommodate one of the swingable parts 56 of a cardancoupling.

This embodiment shows at 57 and 5% seals which enable the provision of acompletely ready unit from which the lubricant will not leak and inwhich the bear ing is protected against gear-wearing particles. Cleanstore handling is now possible.

What is claimed is:

l. Pinion gear transmission comprising a pinion shaft, a pinion wheel atone end of said shaft, connecting means at the opposite end of saidshaft for connecting said pinion wheel and shaft to drive means, ahousing, first and second bearing means axially spaced apart forrotatably supporting said pinion shaft and connecting means relative tosaid housing, each of said bearings means including a plurality ofrolling elements engageable between inner and outer raceways, saidpinion shaft and connecting means moveable axially relative to oneanother thereby to effect displacement of said inner and outer racewaysof said bearing means, to preload said bearing means and means forpermanently fixing said shaft and connecting means with said bearingmeans preloaded, said shaft, bearing means and connecting means formingan integral unit.

2. Pinion gear transmission according to claim 1, characterized in thatthe connecting means extend ra' dially outwardly beyond the inner racesof the bearing.

3. Pinion gear transmission according to claim ll, characterized in thatthe housing part is a common race ring for the bearings, having a radialflange for connecting it to a transmission housing.

4. Pinion gear transmission according to claim 11, characterized in thatthe shaft and pinion form one work piece and the connecting means areundetachably secured to the shaft (FIG. ll).

5. Pinion gear transmission according to claim 1, characterized in thatthe shaft and connecting means form one work piece and the pinion isundetachably secured to the shaft.

6. Pinion gear transmission according to claim ll, characterized in thatthe pinion and the connecting means have concentric shaft formingcylindrical portions fitting into each other (H6. 2).

7. Pinion gear transmission according to claim is, characterized in thatthe inner race surfaces are provided in the outer surface of one and/orboth shaft forming concentric portions.

8. Pinion gear transmission as claimed in claim ll wherein said bearingmeans comprises two rows of rolling elements axially spaced apart, theinner raceway for one of the rows of rolling elements being formedintegrally on the exterior surface of said connecting means and theinner raceway for the other row of rolling elements being formed on saidpinion shaft.

9. Pinion gear transmission as claimed in claim 8 including an annularmember adapted to be connected to said housing and having integrallyformed therein the outer raceways for the rows of rolling elements.

llt]. Pinion gear transmission as claimed in claim 1 wherein saidconnecting means comprises a sleeve member and wherein the opposite endof said pinion shaft telescopically engages in said sleeve and whereinsaid bearing means comprises two axially spaced bearing assemblies, eachbearing assembly comprising inner and outer rings and rolling elementsin the annular space between the rings and including a spacer elementengaging the outer rings of the bearing assemblies to space the same,the inner ring of one of said assemblies abutting a shoulder on thepinion shaft and the inner ring of the other bearing assembly engageableby said sleeve member.

lll. Pinion gear transmission as claimed in claim 1 wherein saidconnecting means is permanently secured to said pinion shaft by means ofwelding.

M. A method. of assembling a pinion gear transmission including a pinionshaft connecting means for rotatably connecting the pinion shaft todrive means, a housing and bearing means rotatably supporting the pinionshaft for rotation relative to the housing consisting of the stepsmounting the bearing means on at least the pinion shaft, positioning theconnecting means in engagement with the bearing means and pinion shaftin a manner to preload the bearing means and perma nently securing theconnecting means to the pinion shaft while the bearing means ispreloaded whereby the connecting means, bearing means and pinion shaftform an integral assembly.

113. The method as claimed in claim 112 wherein the pinion shaft andconnecting means are permanently connected by welding.

M. Pinion gear transmission assembly comprising a pinion wheel, a pinionshaft and connecting means at the end of said shaft opposite the pinionfor connecting it to a drive means, a member for connecting the assemblyto a housing and bearing means including a plurality of rolling elementssupporting the pinion shaft within the housing, characterized in thatthe shaft, the pinion, the connecting means bearing means and the innerraces of the bearings form a unit which after its assembly cannot betaken apart, said bearing means being preloaded and comprising two rowsof rolling elements axially spaced apart, the inner raceway for therolling elements being formed integrally on the exterior surface of saidpinion shaft and the outer raceway for the rolling elements being formedon said connecting member.

115. Pinion gear transmission assembly comprising a pinion wheel, apinion shaft, connecting means at the end of said shaft opposite thepinion for connecting it to a drive means and bearing means supportingthe pinion shaft within the housing and having two rows of rollingelements spaced apart axially, characterized in that the shaft, thepinion, the connecting means, the inner races of the bearing, therolling elements and the outer races of the bearing form a unit whichafter its assembly cannot be taken apart and in which the bearing meansare axially preloaded.

l6. Pinion gear transmission assembly according to claim l5,characterized in that the outer races are formed integrally on the innersurface of a connecting member adapted to connect the unit to thehousing.

117. Pinion gear transmission assembly according to claim 16,characterized in that the pinion, the pinion shaft, the connecting meansand the inner races consists of only one work piece.

=1: e a a a Patent No. 3,792,625 Dated February 19, 1974 Invent d-Sture, Lennart Asberg It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

The following should have been added in the issued patent;

[30] Foreign Application Priority Data 0 June 30, 1970 .Dutch 70.09662Signed and sealed this 31st day of December 1974.

(SEAL) Attest 2 MCCOY 2-1. GIBSON JR. 0.. MARSHALL DANN AttestingOfficer Commissioner of Patents FORM ($69) uscoMM-oc wave-ps0 Y U,SGOVERNMENT PRNTING OFFICE: I," Q 36'334,

1. Pinion gear transmission comprising a pinion shaft, a pinion wheel at one end of said shaft, connecting means at the opposite end of said shaft for connecting said piniOn wheel and shaft to drive means, a housing, first and second bearing means axially spaced apart for rotatably supporting said pinion shaft and connecting means relative to said housing, each of said bearings means including a plurality of rolling elements engageable between inner and outer raceways, said pinion shaft and connecting means moveable axially relative to one another thereby to effect displacement of said inner and outer raceways of said bearing means, to preload said bearing means and means for permanently fixing said shaft and connecting means with said bearing means preloaded, said shaft, bearing means and connecting means forming an integral unit.
 2. Pinion gear transmission according to claim 1, characterized in that the connecting means extend radially outwardly beyond the inner races of the bearing.
 3. Pinion gear transmission according to claim 1, characterized in that the housing part is a common race ring for the bearings, having a radial flange for connecting it to a transmission housing.
 4. Pinion gear transmission according to claim 1, characterized in that the shaft and pinion form one work piece and the connecting means are undetachably secured to the shaft (FIG. 1).
 5. Pinion gear transmission according to claim 1, characterized in that the shaft and connecting means form one work piece and the pinion is undetachably secured to the shaft.
 6. Pinion gear transmission according to claim 1, characterized in that the pinion and the connecting means have concentric shaft forming cylindrical portions fitting into each other (FIG. 2).
 7. Pinion gear transmission according to claim 6, characterized in that the inner race surfaces are provided in the outer surface of one and/or both shaft forming concentric portions.
 8. Pinion gear transmission as claimed in claim 1 wherein said bearing means comprises two rows of rolling elements axially spaced apart, the inner raceway for one of the rows of rolling elements being formed integrally on the exterior surface of said connecting means and the inner raceway for the other row of rolling elements being formed on said pinion shaft.
 9. Pinion gear transmission as claimed in claim 8 including an annular member adapted to be connected to said housing and having integrally formed therein the outer raceways for the rows of rolling elements.
 10. Pinion gear transmission as claimed in claim 1 wherein said connecting means comprises a sleeve member and wherein the opposite end of said pinion shaft telescopically engages in said sleeve and wherein said bearing means comprises two axially spaced bearing assemblies, each bearing assembly comprising inner and outer rings and rolling elements in the annular space between the rings and including a spacer element engaging the outer rings of the bearing assemblies to space the same, the inner ring of one of said assemblies abutting a shoulder on the pinion shaft and the inner ring of the other bearing assembly engageable by said sleeve member.
 11. Pinion gear transmission as claimed in claim 1 wherein said connecting means is permanently secured to said pinion shaft by means of welding.
 12. A method of assembling a pinion gear transmission including a pinion shaft connecting means for rotatably connecting the pinion shaft to drive means, a housing and bearing means rotatably supporting the pinion shaft for rotation relative to the housing consisting of the steps mounting the bearing means on at least the pinion shaft, positioning the connecting means in engagement with the bearing means and pinion shaft in a manner to preload the bearing means and permanently securing the connecting means to the pinion shaft while the bearing means is preloaded whereby the connecting means, bearing means and pinion shaft form an integral assembly.
 13. The method as claimed in claim 12 wherein the pinion shaft and connecting means are permanently connected by welding.
 14. Pinion gear transmission assembly comprising a pinion wheel, a pinion shaft and Connecting means at the end of said shaft opposite the pinion for connecting it to a drive means, a member for connecting the assembly to a housing and bearing means including a plurality of rolling elements supporting the pinion shaft within the housing, characterized in that the shaft, the pinion, the connecting means bearing means and the inner races of the bearings form a unit which after its assembly cannot be taken apart, said bearing means being preloaded and comprising two rows of rolling elements axially spaced apart, the inner raceway for the rolling elements being formed integrally on the exterior surface of said pinion shaft and the outer raceway for the rolling elements being formed on said connecting member.
 15. Pinion gear transmission assembly comprising a pinion wheel, a pinion shaft, connecting means at the end of said shaft opposite the pinion for connecting it to a drive means and bearing means supporting the pinion shaft within the housing and having two rows of rolling elements spaced apart axially, characterized in that the shaft, the pinion, the connecting means, the inner races of the bearing, the rolling elements and the outer races of the bearing form a unit which after its assembly cannot be taken apart and in which the bearing means are axially preloaded.
 16. Pinion gear transmission assembly according to claim 15, characterized in that the outer races are formed integrally on the inner surface of a connecting member adapted to connect the unit to the housing.
 17. Pinion gear transmission assembly according to claim 16, characterized in that the pinion, the pinion shaft, the connecting means and the inner races consists of only one work piece. 